Automatically optimizes your pages to minimize the number of network connections and ensure even third party resources won't slow down page rendering.
https://www.cloudflare.com/features-optimizer
Analytics and Tracking · Application Performance
Get access to data on 548,525 websites that are Cloudflare Rocket Loader Customers. We know of 30,937 live websites using Cloudflare Rocket Loader and an additional 517,588 sites that used Cloudflare Rocket Loader historically and 15,474 websites in the United States.
Get a list of 548,525 websites using Cloudflare Rocket Loader which includes location information, hosting data, contact details, 30,937 currently live websites and an additional 16,369 domains that redirect to sites in this list. 517,588 sites that used this technology previously and 15,474 websites in the United States currently using Cloudflare Rocket Loader.